Gas cooktop



FIG. 1 is a perspective view of a gas cooktop showing our new design, the conventional grates shown in broken lines are for illustrative purposes only and form no part of the claimed design;

FIG. 2 is a top plan view thereof;

FIG. 3 is a right side elevation view thereof, the left side being a mirror image; and,

FIG. 4 is a front elevation view thereof, the rear view being a mirror image. 

The ornamental design for a gas cooktop, as shown and described. 